Answer:
A: 8+9+10=27
9+10+11=30
10+11+12=13
B: 19+20+21
C: There isn't any.
Step-by-step explanation:
It just is lol.
6c^2 - c + 1 + 4c - 2c^2 - 8c
= 4c^2 - 5c + 1
= (4c - 1)(c - 1)
Exponent way n
exponetional way
Answer: The standard error of the mean = 0.5
Step-by-step explanation:
Given : Sample size : n = 144
Standard deviation : 
The formula to find the standard error of the mean is given by :-

i.e. 
Hence, the standard error of the mean =0.5